http://images.google.com/images?hl=en&q=Chevy+2500+master+cylinder&um=1&sa=N&tab=wi
Go to www.schucks.com and put in your vehicle information and the part your looking for, will give you a picture and a price, also availability.
call any one of your local rednecks, they probably have one in their wallet next to their best girl picture.